Temperature Sensing Circuit Using Dual Temperature Coefficients

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Solution Overview

Problem

Existing temperature measurement methods in electronic circuits, such as those involving power transistors, are complex and costly due to the need for precise temperature-independent reference signals, and are susceptible to process fluctuations.

Innovation Solution

A method utilizing two temperature-dependent signals with different temperature coefficients, one positive and one negative, to generate comparison signals that represent specific temperatures, eliminating the need for temperature-independent references and reducing the impact of process fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature-independent reference signals are used for accurate temperature measurement, then measurement precision is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the need for temperature-independent reference signals from the measurement system. By using only temperature-dependent signals with different temperature coefficients, the complex bandgap reference circuitry is removed, simplifying the device while maintaining measurement capability through differential comparison of temperature-dependent signals

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the fundamental parameters of the measurement approach by transitioning from comparing temperature-dependent signals with temperature-independent references to comparing two temperature-dependent signals with different temperature coefficients. This parameter change enables accurate temperature measurement without requiring stable reference signals, thereby reducing circuit complexity

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If temperature-independent reference signals are used for temperature measurement, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive, complex temperature-independent reference circuits with simpler, more manufacturable temperature-dependent signal generators. The use of standard semiconductor components with inherent temperature dependence reduces manufacturing costs while achieving the required measurement precision through signal processing

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If conventional temperature measurement methods are used, then temperature measurement is achieved, but susceptibility to process fluctuations increases

Engineering Contradiction:

Improvetemperature measurement capabilityVSAvoidrobustness against process fluctuations

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The invention applies counterbalancing by using two temperature-dependent signals with opposite temperature coefficients. One signal increases with temperature while the other decreases, creating a differential measurement that counteracts the effects of process fluctuations, substrate variations, and environmental changes, thereby improving reliability

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The invention implements a feedback mechanism where the comparison of two temperature-dependent signals provides information about both the absolute temperature and the effects of process variations. By analyzing the differential behavior of signals with opposite temperature coefficients, the system can compensate for process fluctuations and maintain reliable measurements

Inventive Principle:

Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides accurate temperature measurement with reduced complexity and cost, enhancing robustness against fluctuations and eliminating the need for trimming or calibration.

Implementation Method 1

providing a first temperature-dependent signal having a first temperature coefficient, providing a second temperature-dependent signal having a second temperature coefficient

Methodology Applied

Scientific EffectTemperature coefficient effect: Seebeck Effect

Data Source

PatentUS12540861B2Method for temperature measurement and temperature measuring arrangement

Publication Date: 2026.02.03 INFINEON TECHNOLOGIES AG

AI summary

A method for temperature detection and an electronic circuit for temperature detection are described. The method comprises providing a first temperature-dependent signal (Vctat) having a first temperature coefficient; providing a second temperature-dependent signal (Iptat) having a second temperature coefficient; generating a plurality of comparison signals (Vptat(1)-Vptat(n)) on the basis of the second temperature-dependent signal (Iptat), wherein each of the plurality of comparison signals Vptat(i)) represents a respective temperature (T(1)-T(n)); comparing the first temperature-dependent signal (Vctat) with at least one of the plurality of comparison signals (Vptat(1)-Vptat(n)); and outputting temperature information (TEMP) on the basis of the comparing.